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What is Validity?

When people talk about psychological tests, they often ask whether the test is valid or not. What exactly does this mean? What does it mean for a test to have validity?

Answer: Validity is the extent to which a test measures what it claims to measure. It is vital for a test to be valid in order for the results to be accurately applied and interpreted.

Validity isn’t determined by a single statistic, but by a body of research that demonstrates the relationship between the test and the behavior it is intended to measure. There are three types of validity:

1. Content Validity

For content validity, the constructs the test measures have been linked to the tasks, duties and required KSAOs (knowledge, skills, abilities, other) of targeted jobs.

Put another way, it is the extent to which a tool or measure assesses all facets of the construct or job. For example, a test to be a pilot should measure a person’s ability to takeoff, fly and land an airplane (all necessary for a successful pilot), not just whether or not the person can fly an airplane.

2. Criterion-related Validity

A test is said to have criterion-related validity when it has demonstrated its effectiveness in predicting criterion or indicators of a construct. There are two different types of criterion validity:

Concurrent Validity occurs when the criterion measures are obtained at the same time as the test scores. This indicates the extent to which the test scores accurately estimate an individual’s current state with regards to the criterion. For example, on a test that measures levels of depression, the test would be said to have concurrent validity if it measured the current levels of depression experienced by the test taker.

Predictive Validity occurs when the criterion measures are obtained at a time after the test. Examples of test with predictive validity are career or aptitude tests, which are helpful in determining who is likely to succeed or fail in certain subjects or occupations.

3. Construct Validity

A test has construct validity if it demonstrates an association between the test scores and the prediction of a theoretical trait. Put differently, does the test measure what it purports to measure?

For example, in the case of intelligence tests, if a test is suggested to be an intelligence test but it is a simple vocabulary test, is the assessment measuring a person’s mental capacity, or is it simply measuring a person’s exposure to the words on the test?

Learn more about how Chally applies validity measures to our offerings by visiting www.chally.com or contacting us at 800.254.5995.